Selected language behaviors and linguistic phenomena will be analyzed in terms of the communicative utility of those behaviors and phenomena. The specific phenomenon to be treated in depth is prenominal adjective ordering. In many languages the sequential ordering of adjectives is tightly constrained. Three general classes of psychological hypotheses have been proposed to account for this. These are based, respectively, upon models of (a) speech production mechanisms, (b) speech perception mechanisms, and (c) message production and comprehension mechanisms. Each of the hypotheses proposed is at least consistent with formal linguistic analyses and none can be rejected given the data currently available. Two kinds of data are lacking. First, semantic and other correlates of adjective ordering are known only for English, and one goal of the proposed research is to obtain systematic data for a variety of natural languages. Second, on the basis of the known correlates of adjective ordering we plan to determine the functional determinants of that ordering. We propose to accomplish this in laboratory studies which involve the acquisition of a limited novel lexicon. People will learn sets of novel lexical items which refer to novel stimulus objects and dimensions and attributes of those objects. These novel lexical items will vary in terms of such variables as frequency of usage, privilege of occurrence, and selected semantic properties. During the acquisition of these items no ordering regularities or rules are taught. The degree to which each of the variables of interest control or influence subsequent ordering behavior will reflect the degree to which each of those variables is a functional determinant as well as a correlate of ordering in natural language.